Keane put them ahead in the 79th minute but when Lee Carsley's handling offence shortly afterwards led to an equaliser from the penalty spot - and with it a vital away goal - the Coventry teenager's immaturity showed in a booking for dissent. He will now miss Wednesday's return leg in Bursa, which is set to go ahead despite heavy loss of life in the second of two earthquakes in successive days.
In the end, the return of the other Keane, Ireland's inspirational captain Roy, could not quite compensate for the loss through injury and suspension of a clutch of other players including his regular midfield partner Mark Kinsella, Steve Staunton, Mark Kennedy and Niall Quinn. The Sunderland striker, who had been troubled by a neck injury during the week, was forced to pull out after attempting to prove his fitness in the warm-up, Mick McCarthy receiving permission to alter the team sheet he had already submitted.
Quinn is not certain to play on Wednesday and nor is the Blackburn goalkeeper, Alan Kelly, who was substituted with a groin injury during the second half. McCarthy refused afterwards to throw in the towel or resort to flannel, insisting: "I'm very disappointed with the result but not with our players or the manner in which they played. We were up against a very good side. Turkey will think the tie is over, but I don't believe it is."
The Dublin crowd, although as supportive as ever, may well have been more disappointed than the manager if only because their team had begun with a ferocity that the visitors did well to withstand. Not until the end of the first half were Turkey able to collect themselves and threaten reprisals, before coming out more positively after the interval.
Straight from the kick-off Derby's Rory Delap, starting a full international for the first time, jabbed a diagonal pass into the path of the other wide midfielder Kevin Kilbane, who turned inside a defender and forced the goalkeeper Rustu Recber to turn his fierce shot over the bar. Rustu soon had to make a sprawling save from Robbie Keane and then dealt with two unopposed headers from corners by Kenny Cunningham.
The former Coventry manager Gordon Milne, recently returned from a long stint with various clubs in Turkey, had identified a possible weakness in the air, which proved to be one that Quinn's replacement, Tony Cascarino, could not exploit.
Sergen Yalcin slowly began to exert some influence in midfield and towards half-time Ireland were reminded that they could not afford to leave the back door open in the rush to go out and play.
On the half-hour they were caught for the first time as Umit Davala put in Hakan Unsal, who pulled his shot wide. Gary Breen got in the way of a strong drive from the blonde Abdullah Ercan and Unsal, moving inside Stephen Carr again, curled his shot beyond the far post.
Ireland responded well to fashion their best chance of the half in the 39th minute. Breen's downward header gave Cascarino the opportunity to swing and shoot from eight yards out, Rustu just managing to beat the ball away.
Keen to increase their attacking potential, the Turks sent on a second striker in Arif Erdem, who had scored a hat-trick against Northern Ireland in Belfast, to partner his Galatasaray club-mate Hakan Sukur. The chances, however, were falling to Unsal, who clipped a shot just too high.
Delap came inside to shoot over the bar, but he had been too quiet for too long and was immediately replaced on the right by the left-footed Damien Duff. The next change, shortly afterwards, was an enforced one, with Alan Kelly unable to continue in goal and Charlton's Dean Kiely coming on to earn his first cap.
By the time Cascarino was taken off 15 minutes from the end, McCarthy was spending more and more time by the touchline, venting the frustration shared by a crowd of 33,610.
But the change proved to be inspirational. In the 79th minute, Denis Irwin won back possession after his Manchester United team-mate Roy Keane had lost it and fed Cascarino's replacement, David Connolly. A square pass by the former Wolves man, now of no fixed address in Holland, found Robbie Keane, who steadied himself with impressive calm before beating Rustu.
Only three minutes later that good work was undone when Carsley handled Arif's powerful shot and Tayfur Havutcu converted the penalty.
Republic of Ireland (4-4-2): Kelly (Blackburn); Carr (Tottenham), Cunningham (Wimbledon), Breen (Coventry), Irwin (Man Utd); Delap (Derby), Roy Keane (Man Utd), Carsley (Blackburn), Kilbane (WBA); Cascarino (Nancy), Robbie Keane (Coventry). Substitutes: Duff (Blackburn) for Delap, 52; Kiely (Charlton) for Kelly, 61; Connolly (ex-Feyenoord) for Cascarino, 76.
Turkey (4-5-1): Rustu; Ogun, Alpay (all Fenerbahce), Ali Eren (Besiktas), Hakan Unsal ; Umit (both Galatasaray) Tayfun, Sergen, Abdullah (all Fenerbahce), Tayfur (Besiktas); Hakan Sukur (Galatasaray). Substitutes: Arif Erdem (Galatasaray) for Umit, h-t; Tugay (Galatasaray) for Hakan Unsal, 66; Mert (Kocaelispor) for Sergen, 86.
Referee: M Fisk (Sweden).